The review concluded that general anaesthesia with femoral nerve block or spinal anaesthesia with local anaesthetic and spinal morphine can be used for pain control in total knee arthroplasty when combined with cooling and compression and opioid and non-opioid analgesics. However, due to limitations of the included studies and reporting of review methods the reliability of these conclusions was uncertain.

To evaluate the effects on postoperative pain of analgesic, anaesthetic and surgical interventions in adults undergoing total knee arthroplasty.

MEDLINE and EMBASE were searched from 1966 to November 2005 for English language studies. Search terms were reported.

Randomised controlled trials (RCTs) that evaluated the effects of analgesic, anaesthetic and surgical interventions on postoperative pain scores in adults undergoing total knee arthroplasty and which reported pain, function or adverse events were eligible for inclusion.

Included studies evaluated a multiplicity of agents used in different regimens including regional analgesia, anaesthesia, systemic analgesia and non-pharmacological techniques.

The authors stated neither how papers were selected for the review nor how many reviewers performed the selection.

Studies were assessed for reporting of statistical analysis, whether follow-up was 80 per cent or more, allocation concealment, the Jadad scale (reporting of randomisation, blinding and losses to follow-up) and extent to which the study report adhered to CONSORT (Consolidated Standards of Reporting Trials) guidelines. The authors did not state how the validity assessment was performed.

For each study, means and standard deviations of pain scores were extracted. Pain scores were converted to visual analog scale scores (0 to 100 mm). Pain scores and analgesic use were classified as decreased at the majority or the minority of time points, unchanged or increased. The authors stated neither how data were extracted for the review nor how many reviewers performed the data extraction.

The studies were grouped by regimen, mode of delivery and class of agent, and generally combined in a narrative synthesis. Where three of more clinically homogeneous studies provided adequate data, pooled weighted mean differences (WMD) with 95% confidence intervals (CI) were calculated; fixed-effect models were used in the absence of statistical heterogeneity (p>0.10) and random-effects models otherwise.

Systemic analgesia. Compared to placebo, conventional non-steroidal anti-inflammatory drugs (NSAIDs) reduced pain scores (one RCT) and the use of supplementary analgesia (three RCTs). COX-2-selective inhibitors were superior to placebo in reducing pain scores (four RCTs) and reduced supplementary analgesia (three RCTs). Likewise, strong opioids reduced both pain and supplementary analgesia use (two RCTs). Single RCTs of tramadol, dextromethorphan, ketamine and clonidine showed no consistent decreases in pain scores compared to placebo; morphine consumption was reduced with ketamine and clonidine.

Regional anaesthesia. Some studies reported that a single femoral nerve block (FNB) reduced pain scores (six out of eight RCTs) and supplemental analgesic use (four out of seven studies). Continuous FNB reduced pain scores compared to placebo, no treatment or systematic analgesia (five RCTs). Some studies reported that a preoperative spinal opioid reduced pain scores (four out of four RCTs) and the use of rescue analgesia (two out of four RCTs) compared to control. Lumbar epidural opioids reduced the use of rescue analgesia compared to placebo or systematic analgesia (three RCTs).

Non-pharmacological methods. Overall, there was no benefit of different operative or rehabilitation techniques, continuous passive movement, TENS (transcutaneous electrical nerve stimulation) or patient education on pain control. Cooling and compression techniques reduced morphine consumption (two RCTs) and pain (one RCT).

Further results were reported.

General anaesthesia with femoral nerve block or spinal anaesthesia with local anaesthetic and spinal morphine can be used for pain control in total knee arthroplasty. These techniques can be combined with cooling and compression, paracetamol, conventional non-steroidal anti-inflammatory drugs or COX-2-selective inhibitors and intravenous opioids.

The review question and inclusion criteria were clearly stated. Limiting the search to English language articles listed in two databases may have resulted in the omission of other relevant studies and raised the possibility of publication and language bias. Methods used to select studies, assess validity and extract data were not described and so it was not known whether efforts were made to reduce reviewer errors and bias. Only RCTs were included. Appropriate criteria were used to assess validity and results were reported online. Combining studies in a predominantly narrative synthesis was appropriate in view of the diversity among studies. Appropriate methods were used for the meta-analyses. Evidence appeared to support the authors’ conclusions, but the lack of reporting of review methods and conclusions that were generally based on a small number of studies made it difficult to assess their reliability.

Practice: The authors made detailed recommendations for practice. They stated that the choice of treatment should be based on individual patient risks. The use of weak opioids was recommended for moderate to low-intensity pain only. Some interventions were not able to be recommended due to lack of evidence, namely intra-articular techniques (with or without incisional techniques), alternative peripheral nerve blocks and central neuroaxial techniques.

Research: The authors stated that several agents required further research including corticosteroids, gabapentinoids, ketamine, singe injection and continuous infusion peripheral nerve block, intra-articular/incisional techniques, and use of various regimens of conventional non-steroidal anti-inflammatory drugs and COX-2-selective inhibitors on bone healing and in combination with regional analgesia.

The research group (PROSPECT) is supported by Pfizer Inc. New York, NY, USA.

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.